He cites several reasons why GFRP is ideal for lock and dam components. First, the material is corrosion-resistant, which lowers maintenance costs. “The more maintenance you have, the more delays in the navigational system,” says GangaRao. Locks shut down during maintenance, which can cause thousands of dollars in lost productivity.
In addition, GangaRao felt that WVU could design and install some navigational structures at a lower initial cost than existing materials. Some of the structures require very large timber, and GangaRao says it’s much more difficult to obtain quality wood in those sizes than it was 30 to 50 years ago. “We hope that using GFRP can reduce both initial and life cycle costs,” he says.
WVU began by investigating options for recess filler panels, which are traditionally made of welded steel I-beams, angles and plates. This makes them heavy to lift and susceptible to corrosion. University researchers developed and tested four different FRP recess panel designs, then partnered with Creative Pultrusions in Alum Bank, Pa., to fabricate the one that performed best – a hexagonal FRP superdeck system.
The company pultruded three prototype recess filler panels that are 10 feet long, 12 inches wide and 8 inches thick and include a top surface coating from Rhino Linings®. The panels use a vinyl ester resin and more than 30 layers of fiberglass fabric, including 0/90° and ±45° fabrics. “The fiber orientation is extremely complicated,” says GangaRao. “We are making sure the panels have enough shear capacity as well as enough bonding strength.” The panels have been delivered to the Willow Island Locks near Newport, Ohio, and should be installed this spring.